Geographic border studies are relatively scare, but have the potential to inform bilateral health policies that affect the well-being of female sex workers (FSWs) who work at these borders as well as those individuals who solicit their services, both groups being at high risk for human immunodeficiency virus (HIV). We applied bivariate and multivariate techniques to examine FSWs' HIV knowledge and condom use across three partner types, at the Haiti Dominican Republic border, using data from the Study on Sex Workers (n = 241, 2014). Condom use was significantly lower among FSWs on the Haitian side of the border compared to the Dominican side, yet levels of HIV knowledge were similar; specifically, 81% of respondents on the Dominican side reported using condoms every time they had sex with a client, compared to 38% of peers in Haiti (p < 0.001). After introducing controls, FSWs in Haiti continued to have lower odds of using condoms with clients (p < 0.001), noncommercial partners (p < 0.001), and regular partners (p < 0.05) compared to peers in the Dominican Republic. This unique border study highlights disparities in FSWs' condom use regardless of HIV knowledge. The lack of consistent condom use by FSWs in Haiti has the potential to exacerbate the HIV epidemic at the border and impact both nations' HIV incidence rates.